markowitz is a distinguished professor of history at both john jay college of criminal justice and the city university of new york's graduate center. david rosner is co-director of the center for the history and ethics of public health at columbia university where he also teaches science and history. this is their new book, which revisits a chemical menace you might have thought was behind us, but isn't -- "lead wars: the politics of science and the fate of america's children." >> gerald markowitz, david rosner, welcome. >> thank you. >> thank you. >> your book concludes that after all these years, lead is still a problem. >> absolutely. you know, in some ways the story of lead is a great success. we've reduced the amount of lead in children's blood and we've gotten lead out of gasoline and we've gotten lead out of paint. but there are still children who have too much lead in their blood. and it is endangering their life chances, endangering their futures. >> does it kill? >> it doesn't kill anymore. it used to send kids into convulsions, into comas and into paroxysms and ultimately killed